The present invention relates to a water jacket structure for the cylinder head and cylinder block of an engine and, more particularly, to a water jacket structure with a split cooling system adapted therein to reduce the flow loss of the cooling water and improve the life expectancy of the installed thermostat device.
Generally, the cooling system of an automobile engine maintains the engine at normal operating temperatures and protects engine components such as a cylinder block, cylinder head and pistons from thermal harm. The temperature of the combustion chamber of the engine can reach up to around 2500xc2x0 C.
A split cooling system has been proposed in which separate flow passages of the cooling water are provided for the cylinder head and the cylinder block respectively. That is, a water jacket for the cylinder head and another water jacket for the cylinder block are separated from each other, and an inlet through which the cooling water path is connected from an outlet of a water pump to the water jackets is shared at the frontal side of the engine. Further, the water jackets are independently connected to two outlets, the outlets being respectively formed at rear sides of the cylinder head and the cylinder block, i.e., at the rear side of the engine.
The opening degree of the thermostat device is adjusted in accordance with the temperature of the cooling water to control the flow of the cooling water that communicates with the two outlets of the cylinder head and the cylinder block. Accordingly, the cooling water flows from the water pump through the inlet and split into the water jacket of the cylinder head and the water jacket of the cylinder block. Then the cooling water flows through the interior of the water jackets to be sent through the two outlets into the thermostat device.
However, in the conventional water jackets, the inlet generally has a rectangular cross section, and therefore, a vortex can be formed in the inlet IN to cause pressure loss and flow loss. Further, two outlets are provided for both water jackets, and therefore, the thermostat device which communicates with the water jackets is positioned between the cylinder head and the cylinder block.
Accordingly, the relative behaviors of the cylinder head and the cylinder block lead to a generation of vibration, and therefore, repeated loads are imposed on the thermostat device, thereby aggravating the life expectancy of the thermostat device.
The present invention provides a water jacket structure for a cylinder head and cylinder block of an automobile engine with a split cooling system adapted therein, in which the shape of the inlet of the water jacket is altered to diminish the flow loss, and the position of the outlet for the water jacket of the cylinder block is raised to the same or similar level of the outlet for the water jacket of the cylinder head to extend the life expectancy of the thermostat device.
In accordance with one embodiment of the present invention, the water jacket structure for the cylinder head and cylinder block of an automobile engine with a split cooling system adapted includes water jackets formed at the cylinder head and cylinder block respectively and independently. An inlet is shared between the cylinder head and cylinder block, with its cross sectional area being reduced coming inward. The positions of the two outlets have the same or similar level at the cylinder head.
In an alternative embodiment of the invention, a cooling structure for a cylinder head and a cylinder block of an engine includes first and second water jackets. The first water jacket is formed on the cylinder head and defines a first inlet of a first width. The second water jacket is formed around the cylinder block and defines a second inlet of a second width. Preferably, the first and second widths are substantially the same. A common inlet passage communicates with the first and second inlets. The inlet passage has a width greater than the first and second widths. In a further preferred embodiment, the inlet passage is trapezoidal in shape with the smaller side defining the inlets. The structure may also include first and second outlets, respectively, communicating with the first and second water jackets. The outlets are preferably separately formed on the cylinder head. The second outlet may include a vertical passage configured and dimensioned such that the first and second outlets open at substantially the same level with respect to the engine.